The present invention relates in general to processing of hollow fibers, and in particular to a method of producing bundles of hollow fibers arranged parallel to each other, in which at least one continuous hollow fiber is wrapped by means of a movable guiding device about at least two take-up elements spaced apart from each other, so that a strand of hollow fibers is wound around these take-up elements. This invention relates also to a device for carrying out this method and relates also to a bundle of crimpled or waved hollow fibers.
A method of the aforedescribed kind is known for example from the German publication DE-OS No. 2,259,949. This prior art method is based on the application of flexible hollow fiber continuously wound on a coil or spindle, whereby the hollow fiber is taken off by a rotary guiding device and laid in four half shells arranged in pairs. The convex sides of two half shells engage each other and are clamped together, and the two pairs of engaging half shells are aligned in a plane in such a manner that the clearance between the two pairs corresponds to the length of the hollow fiber bundles.
This prior-art method, however, is unsuitable for making bundles of freshly spun hollow fibers, inasmuch as, after achieving the desired thickness of the bundle, the wrapping of the continuous fiber must be interrupted so long until a set of empty half shells is brought into the working position and fixed. Moreover, this known method permits the production of two partial bundles only, namely the two runs of the completed bundle which is formed by joining together the two partial bundles.
Known are also other methods of producing bundles of hollow fibers, for example from the German publication DE-OS No. 3,102,331, in which the hollow fibers which are reeled on a spool are formed in an annular body of hollow fibers which is subsequently cut into individual bundles. The disadvantage of this known method is the fact that the entire mass of the spool and of the hollow fibers wound thereon must be constantly held in rotation. For this reason, this method is also unsuitable for making bundles of hollow fibers of freshly spun or extruded material. Accordingly, this prior-art method necessitates the use of fibers which are already reeled on a spool. The cutting of the annular body of hollow fibers into individual bundles can be made also only during an interruption of the winding operation, that means during the stopping of the spool.
It is true that there is known a large variety of methods and devices for producing bundles of hollow fibers of the aforedescribed kind, but surprisingly all these prior-art methods are suitable for using hollow fibers which are already reeled on spools, thus necessitating an interruption of the winding process when the wrapped-around strand has attained a desired thickness, and this interruption in the prior-art methods is unavoidable.